Railway tank car heating arrangement

ABSTRACT

A stub-sill railway tank car having a lading outlet centrally disposed on the underside of the tank includes two pairs of spaced-apart saddle bolster plates disposed circumferentially of the tank, two pairs of spaced-apart reinforcing plates respectively disposed adjacent to opposite ends of the tank, each pair of reinforcing plates extending longitudinally of the tank and between each pair of spaced-apart saddle bolster plates and disposed symmetrically with respect to the bottom centerline of the tank to define a passage directly therealong, and a heating assembly on the bottom of the tank including input and output heating conduits disposed in the passage between the reinforcing plates longitudinally of the tank for applying heating fluid directly thereto along the bottom centerline thereof; a system of heating coils and manifolds interconnects the input and output heating conduits.

United States. Patent [151 3,685,458 Price et al. e [451 Aug. 22, 1972 s41 RAILWAY TANK CAR HEATING Primary Examiner-Arthur L. LaPoint ARRANGEMENT I Assistant Examiner-Richard A. Bertsch 72 Inventors: Albert E. Price, Brookfield, Ohio; Mom-mile Mum",

[73] Assignee: General Amenca tion 1571' Amer Corpommn A stub-sill railway tank car having a lading outlet cen- [22] Filed; Jun 30, 1970 trally disposer; on thedunderside :5] the bank incliides two pairs space -apart sa e ster p ates [21] App! SL093 disposed circumferentially of the tank, two pairs of spaced-apart reinforcing plates respectively disposed [52] user. ..105/358, 105/3 0, 105/451, dj t to pp 611918 of the tank, each P of 165 9 reinforcing plates extending longitudinally of the tank 51 Int. Cl. ..B6ld 27/00 and betweeq cad! P pa pa Saddle bolster [58] Field of Search ..l/358, 360,362, 451; Plates and dlsposed y m ri ally with. respectto the 165/69 bottom centerline of the tank to define a passage directly therealong, and a heating assembly on the bottom of the tank including input and output heating ['56] r-1. Cited conduits disposed in the passage, betweenthe reinforc- UNITED STATES PATENTS ing plates longitudinally of the tank for applying heatr v v ingfluid directly thereto along the bottom centerline Bettendorf I thereof. a System f h g coils d manifolds intep g n-1? connects the input and output heating conduits. ar

12 Claims, 7 Drawing Figures I03 120 [I44 I 3? [7'3 I [37 L140- 1 II I I; ll 1 @L r44 J33 g7 us 158 I42 3 I32 14/ 139 I3 I17 I08 I j 23/09 /22 7 7 Y Robert L. Mamen, Sharon, Pa.

Vogel PATENTED M1822 I972 SHEET 1 BF 3 INVENTORS ALBERTE. PRICE ROBERT L. MANSEN m9 QQ RAILWAY TANK CAR HEATING ARRANGEMENT This invention relates in general to storage tanks. More particularly, it relates to external arrangements for heating such tanks and the lading contained therein. It is a general object of this invention to provide an improved arrangement for heating the contents of a stub-sill railway tank car whereby the heating fluid may be applied to the tank wall directly along the longitudinal bottom centerline thereof. t It is an important object of this invention to provide storage tank heated by a heating fluid and comprising an encompassing generally cylindrical side wall disposed substantially horizontally, two end walls respectively closing the opposite ends of the side wall and cooperating therewith to define a closed lading compartment, input means for introducing lading into the lading compartment, output means in the bottom of the side wall for emptying lading from the lading compartment, an input heating conduit disposed longitudinally of the bottom of the side wall and arranged to place the heating fluid in direct contact with the adjacent portion of the side wall, an output heating conduit disposed longitudinally of the bottom of the side wall and arranged to place the heating fluid in direct contact with the adjacent portion of the side wall, the heating conduits lying directly along the bottom centerline of the side wall and cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of the side wall and communicating with the input heating conduit and with the output heating conduit, means for introducing heating fluid into the input heating conduit and means for withdrawing spent heating fluid from the output heating conduit, whereby heating fluid is carried from the input heating conduit through the heating coil to the output heating conduit for direct contact with the bottom of the storage tank along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of the storage tank and the lading contained therein.

It is another object of this invention to provide a storage tank of the type set forth wherein the input heating conduit is a primary input heating conduit, and further including a pair of secondary input heating conduits communicating with, the input heating conduit and disposed longitudinally of the bottom of the side wall on opposite sides of the output heating conduit, and two heating coil assemblies carried by the bottom of the side wall for respectively connecting the primary input heating conduit and. the output heating conduit with the secondary input heating conduits.

It is another object of this invention to provide a storage tank of the type set forth wherein the input heating conduit comprises an input manifold having an inlet and a plurality of outlets, and the output heating conduit comprises an output manifold having a plurality of inlets and an outlet, and further including a plurality of intermediate manifolds carried by the bottom of the wall structure and equal in number tothe inlets of the output manifold, each of the intermediate manifolds having a plurality of inlets and an outlet, the combined total of the inlets of the plurality of intermediate manifolds being equal in number to the outlets of the input manifold, a plurality of first heating coils respectively interconnecting the outlets of the input manifold and the inlets of the intermediate manifolds, and a plurality of second heating coils respectively interconnecting the outlets of the intermediate manifolds and the inlets of the output manifold.

Yet another object of this invention is to provide a railway tank car comprising ,a pair of truck structures, a pair of stub center sills respectively carried by the truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by the centersills, reinforcing structure carried by the bottom of the side wall and extending longitudinally thereof, the reinforced structure having a passage extending longitudinally therethrough directly along the bottom centerline of the side wall, two end walls respectively closing the opposite ends of the side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into the lading compartment, output means in the bottom of the side wall for emptying lading from the lading compartment, first fluid retaining means disposed longitudinally of the passage adjacent to one end of the side wall for defining an input heating conduit in the passage arranged to place the heating fluid in direct contact with the adjacent portion of the side wall, second fluid retaining means disposed longitudinally of the passage adjacent to the other end of the side wall for defining an output heating conduit in the passage arranged to place the heating fluid in direct contactwith the adjacent portion of the side wall, the heating conduits lying directly along the bottom centerline of the side wall cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of the side wall and communicating with the input conduit and with the output conduit, means for introducing heating fluid into the input heating conduit and means for withdrawing spent heating fluid from the output heating conduit, whereby heating fluid is carried from the input heating conduit through the heating coil to the output heating conduit for direct contact with the bottom of the storage tank along substantiallythe entire longitudinal centerline thereof for efficiently heating the bottom of the storage tank and the lading contained therein.

In connection with the foregoing object, it is another object of this invention to provide a railway tank car of the type set forth, wherein the input heating conduit is a primary input heating conduit and further including a pair of secondary input heating conduits communicating with the primary input heating conduit and disposed longitudinally of the bottom of the side wall on opposite sides of the output heating conduit, and two heating coil assemblies carried by the bottom of the side wall for respectively connecting the primary input heating conduit and the output heating conduit with the secondary input heating conduits.

It is another object of this invention to provide a railway tank car of the type set forth, which further includes a pair of saddle bolsters respectively carried by the bottom of the side wall adjacent to the opposite ends thereof and each extending circumferentially thereof for mounting the side wall on the centersills, each of the saddle bolsters having a passage extending therethrough longitudinally of the side wall along the bottom centerline thereof, the reinforcing structure being disposed in the passages through the saddle bolster.

Still another object of this invention is to provide a railway tank car of the type set forth wherein portions of the reinforcing structures are spaced from the bottom of the side wall and cooperate therewith to define the input and output heating conduits.

. Further features of the invention pertain to the particular arrangement. of the parts of the storage tank present invention,

FIG. 2 is an enlarged bottom plan view of the heating arrangement of the railway tankcar illustrated in FIG.

G. 3 is enlarged fragmentary view in vertical section of the heating-arrangement according to the I 7 present invention taken along the line 3-3 in FIG. 1;

FIG. 4 is an enlarged fragmentary view in vertical section of the heating arrangement of the present invention taken along the line 4-4 in FIG. 1;

- FIG. 5 is a further enlarged fragmentary view of a portion of the heating-arrangement of FIG. 2; a FIG. '6 is .a fragmentary view in vertical section,

similar to FIG. 4, of a second embodiment of the heating arrangement of this invention; and

FIG. 7 is a fragmentary view in vertical section, similarto FIG. 4, of a third embodiment of the heating arrangement of this invention.

Referring now to the drawings, and, in particular, to FIG. 1 thereof, there is shown a railway tank car,

' generally designated by the numeral 100, and comprising a relatively. long horiZontally disposed cylindrical side wall 101, the opposite ends thereof-being respec-' tively closed by a pair of generally concave end walls or head members 102 and 103, the side wall 101 and the end walls 102 and 103 cooperating to form a storage tank 105 defining therein an enclosed lading compartment 104. In the top of the side wall 101, adjacent to the" center thereof, are a pair of lading input hatches 106, preferably respectively disposed on opposite sides of the vertical midplane of the side wall 105 normal to the longitudinal axis thereof. The storage tank 105 is supported adjacent'to the opposite ends thereof by a pair of standard truck andwheel assemblies 107, the

truck and wheel assemblies 107 each carrying a stub gravity. Any number of different types of lading may be;

advantageously'carried in the tank 105, both those which are normallyin the'liquid state at'ambient ternperatures, such as vegetable oil, mineral oils, corn Y syrup 1 and various chemical compounds and those end plate 116 thereof. This bottom section 131 thereby which are normally in the solid state at ambient temperatures such as parafiin, lard, etc. However, for effective unloading through the valve unit-109, these various ladings must all be placed in a free-flowing liquid state, which can usually be accomplished by elevating their temperatures. l

The saddle bolster assemblies are respectively disposed adjacent to the opposite ends of thetank 105,

each of the saddle bolster assemblies 110 comprising a pair of spaced-apart arcuate saddle bolster plates 111 and l 12 connected to the outer surface of the side wall 101 and disposed circumferentially thereof and sym-- metrically with respect to the longitudinal bottom centerline thereof. The two reinforcing or bearing plate assemblies 115 are also. respectively disposed adjacent to the opposite ends of the tank 105 and are connected to the outer surface thereof along the longitudinal bottom centerline thereofThe reinforcing assemblies 115 are identically constructed and each includes a generally arcuate end plate 116 and a pair of elongated center plates 117 and 118. Each of the end plates 116 is disposed at the adjacent end of the side wall 101 and extends upwardly around the bottom portion of the associated end wall 102 or 103. The center plates 117 and 118 are preferably identically constructed and are spaced inwardly a short distance fromthe inner end of the end plate 116, the center plates 1 l7 and 118 being spaced apart on opposite sides of the longitudinal bottom centerline of the side wall 101 and extending parallel thereto inwardly of. the inner endsof the stub sills 108. It will be noted that the separation between the end plate 116 and the center plates 117 and 118" defines a passage 113'extending circumferentially of the side wall 101, while the separation between the center plates 11! and 118 defines apassage 114 ex? tending longitudinally .of the sidewall 101 directly along the bottom centerlinethereof. Preferably, each of the center sills l08 comprises pairs of spaced-apart upright beams respectively connected at the upper ends thereof to the center plates 1'17 and 118 of the associated reinforcing assembly 1 15, as by welding. It will therein. The heating assembly 120 includes a hollow input tee. 121 disposed adjacent to the lading drainvalve unit 109and having an inlet'pipe 122 connected thereto for introducing heating fluid thereinto. If desired, an alternate inlet pipe 123 More particularly, theperipheral heating coil includes an elongated straight bottom section 131 communicating at one end thereof with the arm 121a of the input tee "121 and extending therefrom directly along the longitudinal bottom centerline of the side wall 101, through the passage 114 in the adjacent one of the reinforcing assemblies 115, and terminating adjacent to defines a primary input heating conduit for conveying heating fluid from the input tee 1 21 directly along the bottom longitudinal centerline of the tank 105 substantially to one end thereof. The outer end of the bottom section 131 communicates with one arm 132a of a coupling tee 132, the other arms 132b and 132:: of the coupling tee 132 being disposed in the passage 113 of the associated reinforcing assembly 115 and extending circumferentially of the side wall 101. Respectively communicating with the arms 132b and 132C of the tee 132 are a pair of end coil sections 133 each extending circumferentially of the side wall 101 and terminating at a point approximately midway between the top and bottom of the tank 105. Two manifolds 135 are respectively provided adjacent to the upper ends of the end sections 133, each of the manifolds 135 having a pair of inlets 135a and 13517 and an outlet 135C. The upper ends of the end sections 133 are respectively connected by elbows 136 to coupling sections 134a, which in turn respectively communicate with the inlets 135a of the manifolds 135. The outlets 1356 of the manifolds 135 respectively communicate with two straight outer side sections 134 extending longitudinally of the side wall 101 substantially to the opposite end thereof. The opposite ends of the side sections 134 are respectively connected by elbows 136 to a pair of end coil sections 137, each of the end coil sections 137 extending downwardly circumferentially of. the side wall 101 to points adjacent to the opposite ends of the passage 1 13 in the associated reinforcing assembly 115. Disposed in this passage 113 are two arms 138b and 138C of a coupling tee 138, respectively communicating with the inner ends of the end sections 137, the other arm 138a of the tee 138 extending into the passage 114 and communicating with an elongated straight bottom section 139 disposed in the passage 113 and extending directly along the bottom centerline of the side wall 101 and terminating adjacent to the drain valve unit 109. The

bottom section 139 is shaped identically to the section 131 and defines an output conduit for conveying heating fluid directly along the bottom centerline of the tank 105 to an outlet pipe 160. I

It will be noted that the peripheral coil 130 of th heating assembly 120 defines a path for heating fluid from the central portion of the bottom of the side wall 101, directly along the bottom centerline thereof to one end thereof, and then directly back to the opposite end thereof via the coil sections 133, 134, and 137 and then again directly along the bottom centerline of the tank through the bottom section 139 to the outlet 160. The inner or secondary coils 140 of the heating assembly 120 are arranged symmetrically with respect to the bottom centerline of the tank 105 and are identical to each other, whereby only one of the coils 140 will be described in detail. The coil 140 includes a plurality of elongated straight sections including a relatively short section 141, three intermediate length sections 142 and two relatively long sections 143, disposed substantially parallel to one another longitudinally of the side wall 101. More particularly, the section 141 communicates at one end thereof with the elbow 126 and extends therefrom toward the end section 137 closely adjacent to the outer edge of the center plate 1 17 (or 118) of the associated reinforcingassembly 115 and substantially parallel thereto. The coil sections 142 extend substantially the entire distance between the bolster plates 11] (or 112) and, while three of the sections 142 have been disclosed, a greater or lesser number may advantageously be provided. The sections 143 extend substantially the entire distance'between the end sections 133 and 137 of the coil 130, the outer one of the sections 143 communicating at one end thereof with the other inlet 1351) or the associated manifold 135. Adjacent ends of the coil sections 141, 142 and 143 are interconnected by a plurality of elbows 144 to define a sinuous or convoluted path for heating fluid therethrough from the input tee 121 to the associated manifold 135, whereupon the heating fluid in the coil 140 joins with that in the coil and flows therealong to the outlet 160. Thus, it will be seen that the coils cooperate with the coil 130 to directly heat substantially the entire bottom of the side wall 101.

Each of the sections and components of the heating assembly 120 is substantially channel-shaped in transverse cross section and is secured to the outer surface of the side wall-101 as by welding. Referring, for example, to FIGS. 3 and 4 of the drawings, each of the bottom sections 131 and 139 of the peripheral coil 130 includes a pair of spaced-apartside walls 146, connected at the upper ends thereof to the outer surface of the side wall 101, and interconnected at the lower ends thereof by a flat bottom wall 147'. Similarly, each of the coil sections 141 and 142 comprises a pair of spacedapart side walls 148, connected at the upper ends thereof to the outer surface of the side wall 101, and interconnected at the lower ends thereof by an arcuate bottom wall 149. Thus, it will be appreciated that the tank side wall 101 forms an upper wall closing the channel-shaped heating assembly sections and cooperates with these sections to define a fluid channel or passage 145 therethrough. Thus, it will be seen that the heating fluid flowing through the heating assembly 120 is at all times in direct contact with the outer surface of the tank sidewall 101. In particular, the heating fluid is in direct contact with the bottommost portion of the side wall 101 along substantially the entire length thereof.

In use, heating fluid, which may be steam or other suitable fluid, is introduced into the input tee 121 of heating assembly 120 through either the inlet pipe 122 or the inlet pipe 123.- From the input tee 121 the heating fluid is directed simultaneously into three separate paths, viz., the peripheral coil 130 and the two inner coils 140. As described above, the peripheral coil 130 transports the heating fluid through the bottom section 131 directly along the bottom centerline of the tank 105 to one end thereof, through the end sections 133, and then directly back via the side sections 134 to the opposite end of the tank 105, whereupon the fluid is again transported through the bottom section 139 directly along the bottom centerline of the tank to the outlet 160. In this manner, the peripheral coil 130 affords a means for applying the heating fluid directly to the bottom centerline of the tank adjacent to one end thereof and, then, immediately conveying the heating fluid to the opposite end of the tank and again applying it directly to the bottom centerline thereof before the heating fluid has a chance to cool appreciably.

It will be noted, that this path directly along the bottom centerline of the tank 105 is permitted by the unique arrangement of the reinforcing plate assembly 115 with the longitudinal passages 114 therein to accommodate the bottom heating coil sections 131 and 139. Thus, the heating fluid can be applied directly to v the outer surface of the tank 105 along the bottommost portion thereof, without interference by the reinforcing assemblies 115. At no point does the heating fluid path overlie any part of the saddle bolster assemblies 110 or reinforcing assemblies 115, whereby a most efficient heating of the tank contents is achieved with a minimum of heat loss. I

" In addition,-the sections 141 of the inner coils 140 are also disposed closely adjacent to the bottom centerline of the tank 105, whereby the heating fluid may be directly applied to the bottom of the tank immediately upon its, introduction into the heating assembly 120, the-coil sections 131, 139 and 141 all cooperating to apply the most'intense heat directly along or closely adjacentto the bottom centerline of the tank along substantially the entire length thereof. In this manner, as is well-known, a most efficientheating ofthe contents of the tank 105 is achieved, with the heat applied to the bottommost portions of the'tank being dispersed by convection upwardly through the lading in the lading compartment 104. Thus, the lading closest to the drain valve unit 109 is quickly fluidized and can be unloaded while the remainder of the lading is still being heated, thereby reducing the unloading time and total heat energy consumption, since the quantity of lading to be 1 fluidized is continually being reduced. Inorder to complement these convection currents in heating the lading disposed above the bottommost portions of the tank 105, the coils 140 of the heating assembly define sinuous paths back and forthalong the side wall 101 to facilitate the heating of the lading disposed directly along the inner surface of thetank side wall 101, the

heating fluid in the coils 140 joining the heating fluid in the coil 130 at the manifolds 135 for transmittal to the outlet 160; i v j Referring now to FIG. 6 'of the drawings, there is shown an alternative embodiment of the reinforcing assembly 115 of the present invention. In the embodiment of FIG. 6, the central reinforcing plates 117 and l 18'have' been replaced'by a single reinforcing plate,

Referring now to FIG. 7 of the drawings there is shown a third embodiment of the bottom sections of the peripheral coil 130. In the embodimentof FIG. 7. a cover plate 155 is provided between the reinforcing plates 117 and 118, the cover plate 155 underlying the outer surface of the reinforcing plates 117 and51 18 and connected thereto, as by welding. The cover plate 115 closes the passage 114 between the reinforcing plates 117 and 118 and cooperates therewith and with the outer surface of the tank side wall 101 to define the associated heating fluid conduit 145. Thus, the covering plate 155 replaces the heating coil sections 131 and 139 in the embodiment of FIG. 5. It will be, of course, recognized that the embodiment of FIG. 7 may most advantageously be used only when the reinforcing plates 117 and 118 extend substantially the entire length of the tank 105.,

While the heating system of the present invention has been disclosed in conjunction with a substantially cylindrical tank 105, it will be appreciated that the heating,

prising six coil sections 142 and four coil sections 143, various other numbers of these coil sections may be.

used, depending upon the size of the railway car 100,

thelading contained therein and the shippers requirements for heating the lading. 1

From the foregoing, it will beseen thatthere has been provided a novel heating arrangement, particularly adapted for-use witha stub-sill railway tank car,

whereby the reinforcing plates are spaced apart to provide a longitudinal passage therebetween, for. accommodating heating conduits to apply heating fliiid.

directly to the longitudinal bottom centerline'ofthe tank to achieve the most efficient heating of thelading I contained therein. j

a In addition, .there has been provided a heating arrangement for a storage tank comprising a novel system of heating coil sections for applying the most intense heat directly to the bottommost portions of the tank,

' along substantially the entire length thereof. In addi- 154. It will be seen, that the reinforcing plate 150 I cooperates with the adjacent portion of the outer surface of. the tank side wall 101 to define a passage or channel 145 for heating fluid. Thus, the reinforcing plate 150 may be used in place of the central plates 117 and 118 and the bottom coil sections 131 and 139 of V puth atingfluid conduits.

tion, a unique three-branch heating assembly has been the appended claims all such modifications as fall 7 within the true spirit and scope of the invention.

What is claimed is: i

1. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures,

an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side ,wall and extending longitudinally thereof, said reinforcing structure having a passage extending longitudinally therethrough directly along the bottom centerline of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith intercommunication among the three,

to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for emptying lading from said lading compartment, first fluid retaining means disposed longitudinally of said passage adjacent to one end of said side wall for defining an input heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retaining means disposed longitudinally of said passage adjacent to the other end of said side wall for defining an output heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of said side wall and communicating with said input conduit and with said output conduit, means for introducing heating fluid into said input heating conduit and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom of said storage tank along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.

2. The railway tank car set forth in claim 1, wherein said reinforcing structure comprises two reinforcing plates respectively disposed adjacent to the opposite ends of said side wall.

3. The railway tank car set forth in claim 1, wherein said reinforcing structure comprises two pairs of reinforcing plates respectively disposed adjacent to the opposite ends of said side wall, the plates of each of said pairs of plates being respectively disposed along opposite sides of the bottom longitudinal centerline of said side wall and cooperating to define said passage therebetween.

4. The railway tank car set forth in claim 1, wherein each of said first and second fluid retaining means comprises a substantially channel-shaped member disposed in said passage and connected along the entire length thereof to the bottom of said side wall, said side wall closing the open sides of said channel-shaped members and cooperating therewith to define said heating conduits.

5. The railway tank car set forth in claim 1, wherein each of said first and second fluid retaining means comprises a cover plate connected to said reinforcing structure and closing the passage therein for defining said heating conduits.

6. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof, said reinforcing structure having a passage extending longitudinally therethrough directly along the bottom center line of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for emptying lading from said lading compartment, first fluid retaining means disposed longitudinally of said passage adjacent to one end of said side wall for defining a primary input heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retaining means disposed longitudinally of said passage adjacent to the other end of said side wall for defining an output heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a pair of secondary input heating conduits communicating with said primary input heating conduit and disposed longitudinally of the bottom of said side wall on opposite sides of said output heating conduit and arranged to place the heating fluid in direct contact with the adjacent portions of said side wall, two heating coil assemblies carried by the bottom of said side wall, one of said heating coil assemblies communicating with said primary input heating conduit and with said output heating conduit and with one of said secondary input heating conduits, the other of said heating coil assemblies communicating with said primary input heating conduit and with said output heating conduit and with the other of said secondary input heating conduits, means for introducing heating fluid into said input heating conduits and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduits through said heating coil assemblies to said output heating conduit for direct contact with the bottom of said storage tank. directly along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.

7. A railway tank car set forth in claim 6, wherein said secondary input heating conduits are respectively disposed on opposite sides of said reinforcing structure.

8. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, a pair of saddle bolsters respectively carried by the bottom of said side wall adjacent to the opposite ends thereof and each extending circumferentially thereof for mounting said side wall on said center sills, each of said saddle bolsters having a first passage extending therethrough longitudinally of said side wall along the bottom centerline thereof, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof through said first passage, said reinforcing structure having a second passage extending longitudinally therethrough directly along the bottom centerline of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for empty- 1] ing lading from said lading compartment, first fluid retaining-means disposed longitudinallyof. said second passage adjacent to one end of said sidewall for defining an input heating conduit in-said second passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retainingmeans disposed longitudinally of said second passage adjacent to the other end of saidside wall for definingan output heating conduit in said second passage-arranged to place the heating fluid in direct contact with the'adjacent portion of said'side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire-"length thereof,'a heating coil carried by the bottom of said side wall and communicating with said input conduit and with said output conduit, means for introducing heating fluid into said input heating conduit and meansfor'withdrawing spent r, heating fluid from output heating conduit,

, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom of said storage tank along substantially the entire longitudinal.

centerline thereof for efl'iciently heating the bottom of said storage tank and the lading contained therein.

9. The railway tank car setforth in claim 8, wherein each of said saddle bolsters comprises a pair of bolster plates disposed on opposite sides of the bottom centere line of said side wall and spaced-apart to define said first passage therebet ween.

10. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side wall andex tending longitudinally thereof, a first portion of said reinforcing structure being spaced fromthe bottom of said side wall andcooperating therewith to definean input heating conduit extending longitudinallythereof,

arsecond portion'of said reinforcing structure being spaced from the bottom of said side wall and cooperating therewith to define an output heating conduit extending longitudinally thereof, said heating conduits lying directly along-the bottomcenterline of said side I wall and cooperating to extend along-substantially the entire length thereof, a heating coil carried by the bot-- tom of said sidewall and communicating with said input conduit andwith said output conduit, means for introducing heating fluid into said input heating conduit and means for withdrawing spentheating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom-of said storage tank along substantially the entire longitudinal. centerline thereof for efficiently heating thetbottdm of sai v tank car .set forthin claim 10, wherein said reinforcing structure comprises a pair of I 

1. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof, said reinforcing structure having a passage extending longitudinally therethrough directly along the bottom centerline of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for emptying lading from said lading compartment, first fluid retaining means disposed longitudinally of said passage adjacent to one end of said side wall for defining an input heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retaining means disposed longitudinally of said passage adjacent to the other end of said side wall for defining an output heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of said side wall and communicating with said input conduit and with said output conduit, means for introducing heating fluid into said input heating conduit and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom of said storage tank along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.
 2. The railway tank car set forth in claim 1, wherein said reinforcing structure comprises two reinforcing plates respectively disposed adjacent to the opposite ends of said side wall.
 3. The railway tank car set forth in claim 1, wherein said reinforcing structure comprises two pairs of reinforcing plates respectively disposed adjacent to the opposite ends of said side wall, the plates of each of said pairs of plates being respectively disposed along opposite sides of the bottom longitudinal centerline of said side wall and cooperating to define said passage therebetween.
 4. The railway tank car set forth in claim 1, wherein each of said first and second fluid retaining means comprises a substantially channel-shaped member disposed in said passage and connected along the entire length thereof to the bottom of said side wall, said side wall closing the open sides of said channel-shaped members and cooperating therewith to define said heating conduits.
 5. The railway tank car set forth in claim 1, wherein each of said first and second fluid retaining means comprises a cover plate connected to said reinforcing structure and closing the passage therein for defining said heating conduits.
 6. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof, said reinforcing structure having a passaGe extending longitudinally therethrough directly along the bottom center line of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for emptying lading from said lading compartment, first fluid retaining means disposed longitudinally of said passage adjacent to one end of said side wall for defining a primary input heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retaining means disposed longitudinally of said passage adjacent to the other end of said side wall for defining an output heating conduit in said passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a pair of secondary input heating conduits communicating with said primary input heating conduit and disposed longitudinally of the bottom of said side wall on opposite sides of said output heating conduit and arranged to place the heating fluid in direct contact with the adjacent portions of said side wall, two heating coil assemblies carried by the bottom of said side wall, one of said heating coil assemblies communicating with said primary input heating conduit and with said output heating conduit and with one of said secondary input heating conduits, the other of said heating coil assemblies communicating with said primary input heating conduit and with said output heating conduit and with the other of said secondary input heating conduits, means for introducing heating fluid into said input heating conduits and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduits through said heating coil assemblies to said output heating conduit for direct contact with the bottom of said storage tank directly along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.
 7. The railway tank car set forth in claim 6, wherein said secondary input heating conduits are respectively disposed on opposite sides of said reinforcing structure.
 8. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, a pair of saddle bolsters respectively carried by the bottom of said side wall adjacent to the opposite ends thereof and each extending circumferentially thereof for mounting said side wall on said center sills, each of said saddle bolsters having a first passage extending therethrough longitudinally of said side wall along the bottom centerline thereof, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof through said first passage, said reinforcing structure having a second passage extending longitudinally therethrough directly along the bottom centerline of said side wall, two end walls respectively closing the opposite ends of said side wall and cooperating therewith to define a lading compartment therein, input means for introducing lading into said lading compartment, output means in the bottom of said side wall for emptying lading from said lading compartment, first fluid retaining means disposed longitudinally of said second passage adjacent to one end of said side wall for defining an input heating conduit in said second passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, second fluid retaining meanS disposed longitudinally of said second passage adjacent to the other end of said side wall for defining an output heating conduit in said second passage arranged to place the heating fluid in direct contact with the adjacent portion of said side wall, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of said side wall and communicating with said input conduit and with said output conduit, means for introducing heating fluid into said input heating conduit and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom of said storage tank along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.
 9. The railway tank car set forth in claim 8, wherein each of said saddle bolsters comprises a pair of bolster plates disposed on opposite sides of the bottom centerline of said side wall and spaced-apart to define said first passage therebetween.
 10. A railway tank car heated by a heating fluid and comprising a pair of truck structures, a pair of stub center sills respectively carried by said truck structures, an encompassing generally cylindrical side wall disposed horizontally and supported adjacent to the opposite ends thereof by said center sills, reinforcing structure carried by the bottom of said side wall and extending longitudinally thereof, a first portion of said reinforcing structure being spaced from the bottom of said side wall and cooperating therewith to define an input heating conduit extending longitudinally thereof, a second portion of said reinforcing structure being spaced from the bottom of said side wall and cooperating therewith to define an output heating conduit extending longitudinally thereof, said heating conduits lying directly along the bottom centerline of said side wall and cooperating to extend along substantially the entire length thereof, a heating coil carried by the bottom of said side wall and communicating with said input conduit and with said output conduit, means for introducing heating fluid into said input heating conduit and means for withdrawing spent heating fluid from said output heating conduit, whereby heating fluid is carried from said input heating conduit through said heating coil to said output heating conduit for direct contact with the bottom of said storage tank along substantially the entire longitudinal centerline thereof for efficiently heating the bottom of said storage tank and the lading contained therein.
 11. The railway tank car set forth in claim 10, wherein said reinforcing structure comprises a generally channel-shaped member connected along the entire length thereof to said side wall, said side wall closing the open side of said channel-shaped member and cooperating therewith to define said input and output heating conduits.
 12. The railway tank car set forth in claim 10, wherein said reinforcing structure comprises a pair of reinforcing plates respectively disposed adjacent to the opposite ends of said side wall. 